Book excerpt: The distribution of precision-time and time-interval (PTTI) information has been accomplished in the past by various methods. The most accurate method has been the transportation of a cesium frequency standard to the required location and return. In many instances transporting a cesium standard is too expensive for the accuracy of the transfer of PTTI required. Transfer of time via satellite transponders is not new. What is new is the method of computing delay corrections. The technique of a passive one-way timing technique with field correction for atmospheric delay is discussed. (Author).